Welding controller



-C. STANSBURY WELDING CONTROLLER Filed larch 26, 1958 20 coil I Patented "Dec. 31, 1940 PATENT OFFICE WELDING CONTROLLER i Q.

Carroll Stansbury, Wauwatosa, Wia, assignor to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application March 26, 1938, Serial No. 198,202

12 Claims.

This invention relates to improvements in welding controllers.

The system is particularly applicable to socalled stitch welders in which it is desired to close and open a welding circuit repeatedly for timed periods and whereby both the closing and the opening periods may be independently adjusted. The system further provides for control of the moment of closure and opening of the welding circuit with respect to the time phase of the alternating current supplied to the welding electrodes.

The attached drawing is illustrative of one err bodiment of the invention.

In the drawing, I is a welder switch having normally open main contacts I, normally closed auxiliary contacts I and normally open auxiliary contacts I The switch is adapted to close its main contacts upon energization of a magnet Upon energization of the coil I, it attracts a plunger I provided with an extension I which engages a collar I of the switch, to move the same against its bias'. A latch I holds the switch in the closed position after it has been 25 closed by energization of the coil I To return the switch to open position the latch I may be tripped by a coil I. To reduce arcing the contacts I" and I are paralleled by condensers 2 and -3, respectively, the contacts and parallel con- 30 densers being connected between the positive pole of a direct current supply and one terminal of the coils I and I respectively. The other terminal of the coil I is connected to the anode 4 of a gaseous electron tube having also a heated 85 cathode 4 and a grid 4 The cathode 4 may be heatedin any well known manner not shown. The second terminal of the coil I is connected to the anode 5 of a gaseous electron tube 5 having also a cathode 5" and a grid 5. The system further in- 40 eludes a gaseous electron tube 6 having a cathode li, an anode 6 and a grid 6 and a similar tube 1 having a cathode 1, an anode l and a grid 1. The anode 6 of the tube 6 is connected in series with a resistance 8 to the positive terminal 45 of the direct current supply, while the cathode 6" is connected in series with a potentiometer resistance I0 having an adjustable contact I0 and a normally open pilot switch I I to the negative line. The anode I is connected to the positive line 50 through a resistance I2, while the cathode I is connected through a potentiometer resistance I3 to the negative line. has an adjustable contact I3". An adjustable resistance It is connected between the cathode 6 65 and the grid 6 A similar adjustable resistance the grid 5.

Potentiometer resistance I3 I5 is connected between the cathode 1 and the grid 1. A condenser I6-is connected between the anodes 6" and 'I". Condenser I1 is connected between anode I and the'grid 6 while a similar condenser I8 is connected between the grid I and ii the anode 6.

A condenser I 9 is connected between the grid 5 and the negative line, while grid 5 is also connected through a resistance 20, secondary winding 2I ofya transformer 2I and a biasing battery 22 ID to the contact I3; The biasing battery 22 is so connected that its negative terminal is nearest to The cathode 4 is connected to the common terminal of the pilot switch II and the resistor III. A condenser 23 is connected between 15 grid 4 and the cathode 4. The grid 4 is also connected through a resistance 24, a secondary winding 25 of a transformer 25 and a biasing battery 26 to the adjustable contact Ill. The biasing battery 26 is so connected that its negative terminal is nearest to the grid 4.

The primary winding 2I of the transformer 2I is connected to the secondary winding 21 of a phase shift transformer 21, whose three terminals of its primary winding 2I are preferably connected to a 3-phase alternating current circuit which is in synchronism with the alternating current supplying the welding circuit. The primary winding 25 of transformer 25 is connected to a secondary winding 28 of a transformer 28 which 30 is similar to transformer 21, the primary winding 28 of said transformer 28 being connected in parallel to the transformer 21 to the B-phase network.

The contacts I control the primary winding 29 of a welding transformer 29, the secondary winding 29 of which supplies the welding electrodes with energy.

The system heretofore described operates as follows: As long as the pilot switch II is open, 40 current flows from the positive line through the resistance I2, tube to the resistance I3 to the negative terminal of the direct current supply. The grid I of tube 1 has the same potential as the cathode and therefore the tube 1 conducts current which produces a voltage drop in the a resistance I3 which is positive with respect to the grid 5 of tube 5. The aforementioned positive drop is in opposition of the voltage supplied by the biasing battery 22 and is normally so adjusted that the negative voltage of the battery 22 predominates over the voltage drop through the resistance I3 and the tube 5 is non-conducting. However, an alternating voltage is impressed on the transformer winding 2| which produces a voltage in the winding 2|. This voltage is alternating while its phase relative to the welding current in the winding 2! may be adjusted in a well known manner by rotation of the secondary winding 21' with respect to the primary winding 21. The polarity of this voltage is so adjusted that at certain moments of the alternating cycle it makes the resultant grid voltage sufficiently positive to permit conduction through the tube 6 provided the tube circuit is closed. However, with the pilot switch ll open the tube circuit is open at the contacts I and therefore no current can flow through the tube.

,The grid circuit of the tube 4 is arranged in a similar manner to tube 5 as aforedescribed. If now the push button I i is closed current flows from the positive line through the resistance 8, tube 6, resistance I0, push button II to the negative line. When this current begins to flow the potential of the anode 6 and with it the potential of the condenser i6 is suddenly lowered so as to cause a corresponding drop of the potential of the plate of the condenser it which is connected to the anode '1 with the result that the voltage between the cathode 1* and the anode 1 is momentarily too low to permit continuance of current flow through the tube I. At the same time the potential impressed on the condenser 18 is lowered and charges it so as to make grid 1 negative. This prevents restarting of the tube until the charge on the condenser l8 has been dissipated through the adjustable resistance H5.

The flow of current through the tube 6 also initiates a voltage drop through the resistance I 0 which drop is positive with respect to the grid i but the voltage on the grid resulting from voltage drop through resistance l0 and the voltage impressed by the battery 26 is not sufficiently positive to permit starting of current flow through the tube i. However, at a certain time phase of the alternating current supplied to the winding 28 a supplemental voltage is impressed on the winding 25 which raises the resultant voltage 4 so that the tube 4 becomes conducting, thereby momentarily energizing the coil i and closing the circuit i of the welding transformer and supplying the welding circuit with energy. At the same time the normally closed contact l is opened thereby again opening the circuit through the coil i and stopping the tube 4 from conducting current.

After the condenser l8 has become sufficiently discharged the tube 1 again becomes conducting. This causes a sudden drop in the voltage of the anode 'l and through the action of the condenser l8 as aforedescribed, the voltage of the anode 6 becomes sufficiently negative to cause interruption of current flow through the tube 6. This eliminates the positive voltage bias of the grid 4 due to the voltage drop in the resistance l0 and the tube l cannot start again even at the moments when the voltage impressed by the winding 25 is positive.

When the tube 1 becomes conducting an additional positive bias is again supplied to the grid 5 through the voltage drop in the resistance l3 and with a momentary positive voltage in winding 2| the tube may again conduct current. When the switch I is energized and latched in the closed position by the latch the normally open contact I is closed. When therefore the tube 5 becomes conducting the coil i is energized thereby tripping the latch and permitting the switch i to return to theoff position and opening again the contact l The cycle is repeated in that after a certain time the tube 8 again becomes conducting thereby making the tube 1 non-conducting and vice versa. Every time that the tubes 6 or 1 become conducting the corresponding tubes 4 and I become conducting, the moment of initiation of current therethrough being modified by phase adjustment of the voltage in the transformers I1 and 28, respectively. The time during which the tubes 8 and 1 each are non-conducting and thus permit the other tube to conduct current may be regulated by the resistances H and I5 and further regulation may be provided by making the condensers I1 and I8 adjustable. It will thus be seen that with this system the closure of the 1 switch is initiated by action of tube 0 and the period during which it remains closed depends upon the period of conduction of the tube 1 while the moment when the switch is opened is initiated by tube 1 and the period during which 0 it stays open is regulated by the tube 6. It will further be observed that while the tubes 6 and I prepare for the energization of the coils I and I respectively, the exact moment at which the coils are energized depends upon the phase adjustment of the transformers 21 and 28 with respect to the phase of the supply circuit for the welding energy. By proper adjustment of these transformers the welding circuit may be opened and closed at the moment when the welding current passes through zero thus reducing to a minimum the arcing of the main contacts I and also reducing the transients in the circuit due to closure of the welding circuit.

What I claim as new and desire to secure by Letters Patent is:

1. Apparatus for the cyclic control of the flow of current in an alternating current work circuit, comprising, a switch for completing said circuit, electromagnetic means to move said switch to closed position, latching means to maintain said switch closed, electromagnetic means to release said latching means to permit movement of said switch to open position, individual means affording energization of said electromagnetic closing and releasing means, individually adjustable timing means adapted to initiate alternate operation of said last mentioned means at given time intervals, and individual means to modify the effect of said timing means and to initiate said energization at a given time phase of said alternating current.

2. Apparatus for the cyclic control of the flow of current in an alternating current work circuit, comprising, a switch for completing said circuit, a source of direct current, an electromagnetic winding energizable to move the switch to closed position, latching means to maintain said switch closed, an electromagnetic winding energizable to release said latching means, a pair of gaseous electron tubes each having a grid, one each of said tubes being connected in circuit with one each of said windings and said source, means to alternately impress upon each grid a voltage tending to initiate current flow through said tubes alternately and energize the respective winding and means to modify the effect of said last mentioned means in accordance with the time phase of said alternating current circuit to thereby adjust the time phase of starting current flow through the respective winding.

3. In a system for alternately energizing two circuits at spaced intervals and at given moments of the time-phase of an alternating current, in combination, a direct current supply, a pair of to impress an alternating current control voltage on each of said second mentioned tubes to modify their response to said current flow and means to adjust the phase of said control voltages individually with respect to said alternating current.

4. In a system for alternately energizing two circuits at spaced intervals and at given moments of the time phase of an alternating current, in combination, a direct current supply, a pair of gaseous electron tubes one for each circuit con nected to said supply, a pair of energy storage discharge circuits one for each tube affecting the conductance of one of said tubes and responsive to the current flow in the other of said tubes, respectively, a second pair of gaseous electron tubes one in series with each circuit to control the conductance thereof and responsive to the current flow in the respective first mentioned tube, means to impress an alternating current control voltage on each of said second mentioned tubes to modify their response to said current flow, and means-to adjust the phase of saidcontrol voltages individually with respect to said alternating current.

5. Apparatus for the cyclic control of the flow of current in an alternating current work circuit, comprising, a switch for completing said circuit, electromagnetic means to move said switch to closed position, latching means to maintain said switch closed, electromagnetic means to release said latching means to permit move ment of said switch to open position, individual electronic means in circuit with said electromagnetic closing and releasing means, respectively, means to control the energization of one of said electronic means to control the closed period of said switch and to initiate actuation of means to control the other of said electronic means, and means to control the other of said electronic means to control the open period of said switch and to initiate actuation of said one electronic means.

6. Apparatus for the cyclic control of the flow of current in an alternating current work circuit, comprising, a direct current supply, a switch for connecting said circuit to an alternating current supply, electromagnetic means to move said switch to circuit closed position, latching mea s to maintain said switch closed, electromagnetic means to release said latching means to permit movement of said switch to open position, a pair of gaseous electron tubes connected to said direct current supply, an energy storage circuit for each tube ailfecting the conductance of the respective tube and responsive to the current flow in the other tube, a second pair of gaseous electron tubes one for each. on said first mentioned tubes and responsive to current flow in the respective first mentioned tubes, one of said second mentioned tubes being connected in series with said electromagnetic closing means and another of said second mentioned tubes being connected in series with said electromagnetic releasing means to control the conductance thereof, means to impress an alternating current control voltage on each of said second mentioned tubes to modify their response to said current flow. and means to adjust the time phase of said control voltage individually with respect to the time phase of said alternating current supply.

7. Apparatus for the cyclic control of the flow of current in an alternating current work circuit, comprising, a direct current supply, a switch for connecting said circuit to an alternating current supply, electromagnetic means to move said switch to circuit closed position, latching means to maintain said switch closed, electromagnetic means to release said latching means to permit movement of said switch to open position, a pair of electronic tubes connected to said direct current supply, an energy storage circuit for each tube affecting the conductance of the respective tube and responsive to the current flow in the other tube, a second pair of electronic tubes one for each of said first mentioned tubes and responsive to current flow in the respective first mentioned tubes, one of said second mentioned tubes being connected in series with said electromagnetic closing meansand another being connected in series with said electromagnetic releasing means to control the conductance thereof, means to impress an alternating current control voltage on each of said second mentioned tubes to modify their response to said current flow, and means to adjust the time phase of said control voltages individually with respect to the time phase of said alternating current supply.

8. Apparatus for the cyclic control of the flow of current in an alternating current work circuit, comprising, a switch for completing said circuit, a source of direct current, an electromagnetic winding energizable to move the switch to closed position, latching means to maintain such switch closed, an electromagnetic winding energizable to release said latching means, a pair of electronic tubes each having a grid, one of said tubes connected in circuit with each of said windings and said source, means to alternately impress upon each grid a voltage tending to initiate current flow through said tubes alternately and energize the respective winding, and means to modify the effect of said last named means in accordance with the time phase of said alternating current circuit to thereby adjust the time phase of starting the current flow through the respective winding.

9. Apparatus for the cyclic control of the flow of current in an alternating current work circuit, comprising, a switch for completing said circuit, a source of direct current, an electromagnetic winding energizable to move the switch to closed position, latching means to maintain such switch closed, an electromagnetic winding energizable to release said latching means, a pair of electronic tubes each having a grid connected in circuit with each of said windings and said source, means to impress upon each grid a voltage maintaining the respective tube non-conducting, means to vary said voltage to make the tube conducting and to initiate current flow therethrough. and energize the respective winding, and means to modify the effect of said last mentioned means in accordance with the time phase of said alternating current circuit to thereby adjust the time phase of starting the current flow through the respective winding.

10. Apparatus for the cyclic control of the flow of current in an alternating current work circuit. comprising, a switch for completing said circuit, a source of direct current, an electromagnetic winding energizable to move the switch to closed position, latching means to maintain such switch closed, an electromagnetic winding energisable to release said latching means, a pair of electronic tubes each having a grid, each of said tubes being connected in circuit with one of the respective windings and said source, means to impress upon said grids a voltage to maintain the respective tube non-conducting, means to vary said voltage to initiate current now therethrough to alternately energize the respective windings, means to vary the time interval between successive alternations of said voltage variations, and means to modify the efi'ect of said last mentioned means in accordance with the time phase of said alternating current circuit to thereby adjust the time phase of starting the current flow through the respective winding.

11. Apparatus for the cyclic control of the fiow of current in an alternating current work circuit, comprising, a switch for completing said circuit, a source of direct current, an electromagnetic winding energizable to move the switch to closed position, latching means to maintain said switch closed, an electromagnetic winding energizable to release said latching means, a first electronic tube connected in circuit with said closing winding and said source and having a grid, a second electronic tube connected in circuit with said release winding and said source and having a grid, 9. third and a fourth electronic tube connected to said source and each having an anode and a grid, energy storage means associated with each of the two last mentioned tubes and connected to produce simultaneous transient potentials on their respective anode and grid as a fuction of starting of current flow in the other tube, adjustable discharge circuits connected to said grids for controlling the time interval during which the grids maintain their respective tubes non-conducting, a connection between the grid of the first tube and the third tube and between the grid of the second tube and the fourth tube, respecetively, to energize the respective grid of said first and second tube for initiation of current flow therethrough in response to 'fiow of current in the third and fourth tube,\respectively, and means to modify said energization in accordance with the time phase of said alternating current circuit. to thereby adjust the time phase of starting of the current flow through the respective winding.

12. Apparatus for the cyclic control of the fiow of current in an alternating current work circuit, comprising, a switch for completing said circuit, a source of direct current, an electromagnetic winding energizable to move the switch to closed position, latching means to maintain said switch closed, an electromagnetic winding energizable to release said latching means, a first gaseous electron tube connected in circuit with said closing winding and said source and having a grid, a second gaseous electron tube connected in circuit with said releasing winding and said source and having a grid, a third and a fourth gaseous electron tube connected to said source and each having an anode and a grid, energy storage means associated with each of the last mentioned tubes and connected to produce simultaneous transient potentials on their respective anode and grid as a function of starting of current flow in the other tube, adjustable discharge circuits connected to said grids for controlling the time interval during which the grids maintain their respective tubes non-conducting, a connection between the grid of the first tube and the third tube and between the grid of the second tube and the fourth tube, respectively, to energize the respective grid of said first and second tubefor initiation of current flow therethrough in response to a flow of current in the third and fourth tube, respectively, and means to modify said energization in accordance with the time phase of said alternating current circuit to thereby adjust the time phase of starting of the current flow through the respective winding.

CARROLL BTANSBURY. 

